Libraries are only used when they're accessed (that's why there's the handy
'flushlibs' command. "Developers only" my a**, I've used it all the time for years). Devices (that are mounted) are used all the time. They use however much memory you've assigned them as a buffer, plus a little bit more.
Also +1 for Env-Handler, for all your stuff in ENVARC: / ENV:.
Obviously a lot of variables depending on version of the OS, which processor, etc. Cheers, and welcome to the forum!